package com.devunion.bogdan.model.project;

import org.apache.commons.io.FileUtils;
import org.apache.commons.lang.StringUtils;

import javax.imageio.ImageIO;
import javax.swing.*;
import java.io.*;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.awt.image.PixelGrabber;
import java.awt.image.ColorModel;

/**
 * @author Victar Liaskovich
 */
public class ImageHelper {
    private static final String IMAGE_PREFIX = "Page_";
    private static final String IMAGE_FORMAT = "png";

    private RelativePathConverter relativePathConverter;

    private static ImageHelper instance;

    private String projectName;

    private ImageHelper() {
    }

    public static ImageHelper getInstance() {
        if (instance == null) {
            instance = new ImageHelper();
        }

        return instance;
    }

    public void setProjectName(String projectName) {
        this.projectName = projectName;
    }

    public String saveImage(Image image, Integer pageNumber) throws IOException {

        // the directory to upload to
        String uploadDir = relativePathConverter.projectPath(projectName);

        // Create the directory if it doesn't exist
        File dirPath = new File(uploadDir);

        if (!dirPath.exists()) {
            FileUtils.forceMkdir(dirPath);
        }

        String path = IMAGE_PREFIX + pageNumber + "." + IMAGE_FORMAT;

        ImageIO.write(
                toBufferedImage(image),
                IMAGE_FORMAT,
                new File(uploadDir, path)
        );

        return path;
    }

    public Image loadImage(String path) throws IOException {

        if (StringUtils.isBlank(path)) {
            return null;
        }

        File fileToLoad = new File(relativePathConverter.getAbsolutePath(projectName, path));

        if (!fileToLoad.exists() || fileToLoad.isDirectory()) {
            return null;
        }

        return ImageIO.read(fileToLoad);
    }

    private static BufferedImage toBufferedImage(Image image) {
        if (image instanceof BufferedImage) {
            return (BufferedImage) image;
        }

        // This code ensures that all the pixels in the image are loaded
        image = new ImageIcon(image).getImage();

        // Determine if the image has transparent pixels; for this method's
        // implementation, see e661 Determining If an Image Has Transparent Pixels
        boolean hasAlpha = hasAlpha(image);

        // Create a buffered image with a format that's compatible with the screen
        BufferedImage bimage = null;
        GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment();
        try {
            // Determine the type of transparency of the new buffered image
            int transparency = Transparency.OPAQUE;
            if (hasAlpha) {
                transparency = Transparency.BITMASK;
            }

            // Create the buffered image
            GraphicsDevice gs = ge.getDefaultScreenDevice();
            GraphicsConfiguration gc = gs.getDefaultConfiguration();
            bimage = gc.createCompatibleImage(
                    image.getWidth(null), image.getHeight(null), transparency);
        } catch (HeadlessException e) {
            // The system does not have a screen
        }

        if (bimage == null) {
            // Create a buffered image using the default color model
            int type = BufferedImage.TYPE_INT_RGB;
            if (hasAlpha) {
                type = BufferedImage.TYPE_INT_ARGB;
            }
            bimage = new BufferedImage(image.getWidth(null), image.getHeight(null), type);
        }

        // Copy image to buffered image
        Graphics g = bimage.createGraphics();

        // Paint the image onto the buffered image
        g.drawImage(image, 0, 0, null);
        g.dispose();

        return bimage;
    }

    private static boolean hasAlpha(Image image) {
        // If buffered image, the color model is readily available
        if (image instanceof BufferedImage) {
            BufferedImage bimage = (BufferedImage) image;
            return bimage.getColorModel().hasAlpha();
        }

        // Use a pixel grabber to retrieve the image's color model;
        // grabbing a single pixel is usually sufficient
        PixelGrabber pg = new PixelGrabber(image, 0, 0, 1, 1, false);
        try {
            pg.grabPixels();
        } catch (InterruptedException e) {
        }

        // Get the image's color model
        ColorModel cm = pg.getColorModel();
        return cm.hasAlpha();
    }

    public void setRelativePathConverter(RelativePathConverter relativePathConverter) {
        this.relativePathConverter = relativePathConverter;
    }
}
